1. Field of the Invention
The present invention relates generally to rotors and electrical machines using rotors, and, more particularly, but not by way of limitation, to rotors and electrical machines using rotors that include trapped-field magnet (TFM) bulks.
2. Description of Related Art
Rotors and machines using rotors have been known in the art for some time. Electrical machines such as motors traditionally include brushes and a rotor with wire windings. Such traditional winding-based rotors may be relatively inefficient compared with PM rotors, and PM rotors may be made smaller than traditional winding-based rotors for a given capacity or output. Rotors with superconductor wires instead of permanent magnets have been attempted.
Current high-temperature superconductor (HTS or HTSC) rotors and machines generally address niche markets, and may provide a modest improvement in size, weight, and efficiency over PM rotors and machines. However, this modest improvement typically comes with a high premium cost. The majority of current HTS machines use superconductor wires.